Pressure sensor



Jan. 16, 1962 G. wim-Riss PRESSURE SENSOR Filed Dec. 19, 195s ,H21....Ial. f

INVENTOR.

` s mmm Rf 9 x4, A7' TORNEKS 3,017,472 Patented Jan. 16, 1962 3,017,472PRESSURE SENSOR George Wintriss, Carversville, Pa. Filed Dec. 19, 1958,Ser. No. 781,727 7 Claims. (Cl. 200-83) This invention relates toapparatus for determining fluid pressure of a predetermined limit. Theinvention is intended for use Wi-th control equipment and moreespecially with equipment that stops the operation of a machine if apressure rises to a certain value.

It is `an object of the invention to provide improved apparatus Iforsensing pressure above -a predetermined limit, and to provide a verysimple and reliable device for the purpose, the device being capable ofoperating at Very high fluid pressures. i

The pressure sensing apparatus of this invention employs a diaphragmwith edge sealing, a center electrical contact and mechanical loading ofthe diaphragm at angularly spaced locations around the center closeenough to'- gether to maintain a relatively even distrib-ution of theloadingT around the center.

Other objects, features,` and advantages of the invention will appear orbe pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like referencecharacters indicate corresponding parts in all the views:

FIGURE 1 is a vertical sectional view of a pressure sensor made inaccordance with this invention; and

FIGURE 2 is a sectional View on t-he line 2-2 of FIGURE l.

The construction illustrated includes a lower housing 10 having itslower outside surface formed with threads 11 for screwing into anopening from which the pressure Huid is to be supplied. A conduit 12extends axially through the bottom of -the lower housing and communi-There is a lip 16 surrounding the upper end of the conduit 12.

An 'O-ring 18 lits into an annular groove 20 around and adjacent to aside wall 22 of a recess in the top of the lower housing 10. A diaphragm24 extends across the chamber `14 and rests on the lip 16 and the'O-ring 18. The lower housing 10 and the diaphragm 24 are preferablymade of metal and the circumference of the diaphragm contacts firmlywith the s-ide wall 22 of the metal of the lower housing. Spring steelis particularly good material for the diaphragm.

An insulator 26 extends across the upper end of the lower housing '10'and is preferably of the same overall shoulder 28 which lits snugly intothe recess provided by the side wall 22; and the bottom of the shoulder28 contacts with the top of the diaphragm 24' to hold the diaphragm downaga-inst the `O-ring 18.

The bottom surface of the insulator 26 inward from the shoulder 28 risesprogressively toward the center of the insulator and provides a domeceiling for the chamber 14. Thus the insulator 26 is an intermediateportion of the housing and forms the top of the chamber 14. Theinsulator 26 has a flat annular surface 30 extending radially outwardfrom the shoulder 28 and this -annular surface contacts with acorresponding and confronting surface 32 on the lower housing 10. g

A contact holder 34 lits with a press lit into an axial bore 36 throughthe insulator 26. 'I'his holder 34 has a bottom surface `forming acontinuation of the domeshaped surface of the insulator, and the holder34 is actually the center portion of the insulator. Both the insulator26 and the contact holder 34 are made of electrical insulating Imaterialand preferably plastic. A metal ct 40 is located at or near the centerof the contact holder 34 and projects for some distance below theimmediately surrounding surface at the top of the chamber 14.

At angularly-spaced locations around and radially spaced from thecontact 40, 'there are a plurality of loading pins 42 extending throughcylindrical openings in the contact holder 34. These pins 42 arepreferably made of electrical insulating material, such as the contact40,

42 cont-act with the top surface of the diaphragm 24; and the upper endsof the pins 42 bear against `a plate 44 in the lower end of a guide-way46 in an upper housing 48.

Bores 50` at angularly spaced locations around the upper housing 48 haveshoulders 52 at an intermediate level and there is a screw 54 in eachbore with a head that bears against the shoulder 52, and a shank thatextends through openings 56 in the insulator 26 and that threads intoother openings 58 in the lower housing 10. The bores 50 and openings 56are not threaded. The Screws 54 attach the upper housing 48 -to thelower housing 10' with the insulator 26 iirmly clamped between them.

The plate 44 is pressed down against the pins 42 by a spring v60 locatedin the guideway 46, and there is a nut 62 at the upper end of the spring60. A screw 64 threads serve to hold the screw 64 in a generallycentered position. The upper end of the screw 64 contacts with a topwall 66 of the upper housing 48. There is an opening 68 through the topwall 66 above 4the end of the screw 64 but of smaller cross section thanthe screw 64. A screw driver can be inserted through the opening 68 toengage a slot in the upper end of the screw 64. As `the screw 64 isturned in one direction, it

after the tension `of the spring h-as been adjusted to a desired value.Rotation of the nut 62 and screw 64 as a unit will not change thepressure of the spring 60; and with the set screw 70 tight, the nut `62and screw 64 turn as a unit if either one of them turns.

A conductor 72 leads from the center contact 40 and a passage in theinsulator 26 to -a location outapparatus for connection with a loadcircuit such as control equipment.

In the operation of the is supplied to the conduit diaphragm through theplate 44 and pins 42.

lf the iiuid pressure in the conduit 12 rises high enough to force thediaphragm 24 away from the lip 16, then iluid enters the chamber thecenter Contact 40 to close an electric circuit to the conductor 72. Themetal lower housing 10 and the metal diaphragm 24 are part of theelectric circuit.

Fluid under the diaphragm 24 thrusts the 0-ring 18 outwardly against theside wall 22 and into the corner where the diaphragm 24 meets the sidewall 22 so that no fluid can escape into the part of the chamber 14above the diaphragm. Even if iluid could escape around the edges of thediaphragm, however, no gas pressure could build up on the top side ofthe diaphragm because the pins 42 have a running clearance in theopenings through the contact holder 34 and this provides for escape ofgas along the pins. The upper housing 48 above the contact holder 34 isopen to the atmosphere.

The preferred embodiment 'of the invention has been illustrated anddescribed. Terms of orientation are, of course, relative; and changesand modifications can be made, and some features can be used inditterent combinations without departing from the invention as delinedin the claims.

What is claimed is:

1. A pressure sensor comprising a housing having a chamber therein, anelectric circuit, a diaphragm cornprising a part of the electriccircuit, said diaphragm being in the chamber and forming a partitionacross the chamber dividing the chamber into upper and lower portions, aconduit extending through the housing and opening into the lower portionof the chamber below the diaphragm, an electrical contact in saidcircuit and located in the upper portion of the chamber and confrontingthe diaphragm across an unobstructed space of the chamber, resilientloading means exerting force against the diaphragm to hold the diaphragmdown and spaced from said contact, the diaphragm being movable upwardlyar enough to touch the contact and constituting part of an electriccircuit, and means for controlling the degree of uid pressure requiredunder the diaphragm to move the diaphragm into position to touch saidcontact.

2. A pressure sensor comprising a housing having a chamber therein, adiaphragm in the chamber and form ing a partition across the chamberdividing the chamber into upper and lower portions, a conduit extendingthrough the housing and opening into the lower portion of the chamberbelow the diaphragm, an electrical contact in the same chamber with thediaphragm but in the upper portion of the chamber, resilient loadingmeans exerting force against the diaphragm to hold the diaphragm downand spaced from said contact, the diaphragm being movable upwardly farenough to touch the contact and constituting part of an electriccircuit, and means for controlling the degree of iluid pressure requiredunder the diaphragm to move the diaphragm into position to touch saidcont-act, and in which the housing is of composite construction andthere is an element made of electrical insulating material forming atleast a part of the top of the chamber and the contact is carried by theinsulating element, and there is a conductor extending through theinsulating material yfrom said contact.

3. A pressure sensor comprising a housing having a chamber therein, adiaphragm in the chamber, a conduit extending through the housing andopening into the chamber below the diaphragm, an electrical contact inthe chamber above the diaphragm, resilient loading means holding thediaphragm down and spaced from said contact, the diaphragm being movableupwardly far enough to touch the contact and constituting part of anelectric circuit, and means for controlling the degree of uid pressurerequired under the diaphragm to move the diaphragm into position totouch said contact, the housing being of composite construction with anelement of electrical insulating material forming at least a part of thetop ofthe chamber, and with the Contact carried by the insulatingelement, a conductor extending through the insulating material from saidcontact, and in which the resilient loading means includes a pluralityof pins extending through holes in the insulating material and for somedistance above the upper termination of the insulating material, theholes being rat angularly-spaced loca` tions around the contact, a platein contact with the upper ends of the pins, and a spring loading saidplate.

4. The pressure sensor described in claim 3, and in which the pins areat -angularly spaced locations around the circumference of a circle andthe contact is at the center of the circle.

5. A pressure sensor comprising a housing having a chamber therein, adiaphragm in the chamber and forming a partition -across the chamberdividing the chamber into upper and lower portions, a conduit extendingthrough the housing and opening into the lower portion of the chamberbelow the diaphragm, an electrical contact -in the same chamber with thediaphragm but in the upper portion of the chamber, resilient loadingmeans exerting force against the diaphragm to hold the diaphragm downand spaced from said contact, the diaphragm being movable upwardly farenough to touch the contact and constituting part of an electriccircuit, and means for controlling the degree of fluid pressure requiredunder the diaphragm to move the diaphragm into position to touch saidcontact, and in which the chamn ber has a dome-shaped top, and a seat atthe end of the conduit, the diaphragm being held in contact with theseat to limit the area of the diaphragm which is exposed to the pressurein the conduit.

6. A pressure sensor comprising a housing having a chamber therein, adiaphragm in the chamberand forming a partition across the chamberdividing the chamber into upper and lower portions, a conduit extendingthrough the housing and opening into the lower portion of the chamberbelow the diaphragm, an electrical contact in the same chamber with thediaphragm but in the upper portion of the chamber, resilient loadingmeans exerting force against the diaphragm to hold the diaphragm downand spaced from said contact, the diaphragm being movable upwardly farenough to touch the contact and constituting part of an electriccircuit, and means for controlling the degree of fluid pressure requiredunder the diaphragm to move the diaphragm into position to touch saidcircuit, and in which there is an O-ring located in a depression in thebottom wall of the chamber under the peripheral portion of thediaphragm.

7. A pressure sensor comprising a housing having a lower portion with athreaded end for screwing into a pressure connection, an upper portionconnected to the lower portion by clamping screws and with an insulatingelement clamped between the upper and lower portions of the housing, achamber within the housing formed between recessed areas of confrontingfaces of the lower portion of the housing and the insulating element, ametal diaphragm within the chamber and forming a partition across thechamber, an annular recess in the lower wall of the chamber around thecircumference of the chamber for holding an O-ring which seals thediaphragm against leakage of fluid around the edges of the diaphragm,the lower portion of the housing having a center conduit leading intothe chamber under the diaphragm and opening through a boss in the bottomwall of the chamber, the boss having end faces against whichthediaphragm seats to prevent escape of fluid from the passage, a springcarried by the upper portion of the housing; a plate against which thespring presses, pins located at angularly spaced regions around a circleand extending through the insulating element and into contact with thetop of the diaphragm for transmitting the pressure of the spring to thediaphragm, an electrical contact on the top wall of the chamber inposition to be touched by the diaphragm when pressure under thediaphragm exceeds the pressure transmitted from the spring through thepins, and means for adjusting the pressure of the spring. Y

(References on following page) 5 References Cited n the ie of thispatent UNITED STATES PATENTS 6 Kendall et al. Jan. 8, 1957 Reese et al.July 2, 1957 FOREIGN PATENTS Great Britain Ian. 18, 1934 Great BritainApr. 1, 1949

